Counterbalancing system



Feb. 21, 1967 J. R. LOGAN 3,304,670

COUNTERBALANCING SYSTEM Filed Feb. 24, 1964 2 Sheets-Sheet 1 JAMES R. LOGAN INVENTOR 14 TTO/PNEKS Feb. 21, 1967 J. R. LOGAN COUNTERBALANCING SYSTEM 2 Sheets-Sheet 2 Filed Feb. 24, 1964 a um Q Q mw vm bx Ska. mm wwg :9, JAMES R. LOGAN INVENTOP ATTORNEYS United States Patent 3,304,670 fiflUNTlERBALANCTNG SYSTEM James R. Logan, 2229 Logan Court,

Modesto, Calif. 95351 Filed Feb. 24, 1964, Ser. No. 346,665 8 Claims. (Cl. 5266) The present invention relates to a counterbalancing system for elevationally positionable elements and more particularly to such a system which maintains the elements in selected positions of adjustment and is adapted to be quickly interchangeably mounted in a variety of locations on the elements. While the structure of the present invention is shown and described herein as specifically adapted to a camper enclosure having predetermined upper and lower telescopically related elements adapted for support on an automotive vehicle, it will be apparent that the system may also be used with other elevationally positionable elements such as doors, windows, blinds, shades, screens and the like.

Camper enclosures are commercially available for mounting on pickup trucks, trailers, and the like and provide telescopically related upper and lower sections. Such telescopic structures are provided so as to enable the elements to be collapsed to present a low profile minimizing wind resistance, to provide a lower center of gravity for safer transport, and to facilitate parking in garages and carports having a minimum of overhead space. A system of hydraulic jacks is conventionally provided between the upper and lower sections for raising the upper section of the enclosure. dependable particularly when it is desired to maintain the upper section in an elevated position for an extended period. The hydraulic jacks require a large number of seals which are subject to objectionable leakage which, if not controlled, permits gradual descent of the upper section. Furthermore, such hydraulic systems require costly pumps and hoses which add considerable weight to the vehicle and are somewhat difiicult to install and maintain. The mechanical elevating mechanisms usually provide manual cranking devices and have not been as popular as desired because of the physical effort required to raise the upper sections of the enclosures.

Therefore, it is an object of the present invention to provide an improved counterbalancing system for elevationally positionable elements such as telescopic camper enclosures and the like.

Another object is to provide such an improved counterbalancing system which is capable of maintaining the elements in selected positions of adjustment.

Another object is to provide a counterbalancing system which readily accommodates elements of varying weights with a minimum of adjustment.

Another object is to provide a counterbalancing system of the character described which can be easily mounted on such elements in a variety of locations.

Another object is to provide a counterbalancing system which is readily adapted for mounting on existing structures.

Another object is to provide a counterbalancing system which is lightweight, portable, economically manufactured, and is easily installed and maintained.

Other objects and advantages of the present invention will subsequently become more clearly apparent upon reference to the following description in the specification.

In the drawings:

FIG. 1 is a perspective view of an embodiment of the present invention mounted on a telescoping camper enclosure borne on a pickup truck.

FIG. 2 is a longitudinal vertical section through the counterbalancing system of FIG 1.

FIG. 3 is a longitudinal horizontal section through the Such system has not proved counterbalancing system taken generaly on line 3-3 of FIG. 2.

FIG. 4 is a transverse vertical section through the system taken generally along the line 44 of FIG. 2.

Referring more particularly to the drawings, a counterbalancing system embodying the principles of the present invention is indicated generally by the reference numeral it). As shown in FIG. 1, the system is adapted to be mounted on a camper enclosure 11 supported on a pickup truck 12. The enclosure includes a lower wall portion 14 having forward and rearward panels 15 and 16, respectively, and opposite side panels 17 upwardly extended from the bed of the truck. The rearward panel 16 has a door 18 with the front, rear, and side panels providing a continuous upper edge 19. A plurality of outer corner guide members 2t) of angle iron are mounted on the lower wall portion 14.

The camper enclosure 11 also includes an upper wall portion 25 which has forward and rearward panels 27 and 28 and opposite side panels 29 arranged in circumscribing telescopic relation to the lower wall potrion 14. The panels provide a lower edge 30 which is adapted to rest on the upper walls of the pickup truck in its fully telescoped or collapsed position, as shown in FIG. 1. The rearward apnel 28 provides a door 32 registered with the door 18 of the lower wall portion. The upper wall portion also provides a top panel 33 integral with the front, rear and side panels which is adapted to support baggage or other objects such as a boat indicated by the reference numeral 34 in FIG. 17 A plurality of inwardly disposed corner guides 35 of angle iron are mounted within the upper wall portion 25 in sliding relation with the corner guides 20 on the lower wall portion 14. The corner guides thereby also serve as spacers to provide a continuous chamber 36 between the front, rear and side panels of the upper and lower wall portions of the enclosure to accommodate portions of the counterbalancing system hereinafter to be described.

The counterbalancing system 10 provides an elongated frame as having opposite end plates 41 and 42 interconnected by a pair of rail members 43, all of lightweight sheet material such as aluminum, stainless steel or the like. The end plates include outer flanges 44. The frame is secured as by bolting to the forward panel 27 adjacent to the top panel 33 of the upper wall portion 25 in transversely extended relation between the side panels 29 of the upper wall portion. As will subsequently become apparent, the frame may be attached in substantially any desired position on the front, rear or side panels of the enclosure. A housing 46 is mounted in covering relation on the frame to provide a compartment 4'7 to accommodate the counterbalancing system. The housing is connected by a plurality of cap screws 43 screw threadably received within the outer end flanges 44 of the frame.

As best shown in FIG. 2, a spring force adjusting or take-up unit 50 is mounted on the end plate 42 of the frame on a shaft 52 rigidly aflixed as by welding t0 the end plate 42. The take-up unit includes a pair of axially spaced dies 54- which are rotatably mounted on the shaft 52. The discs are interconnected by a hub and by a plurality of circumferen-tially equally spaced pins 56 disposed adjacent to the periphery of the discs. A ratchet pawl 58 is pivotally mounted on the end plate 42 of the frame and provides an end 59 extended between pairs of adjacent pins 56 at an angle to permit rotation of the discs in a counterclockwise direction, as viewed in FIG. 2, but which prevents rotation in the opposite or a clockwise direction. An opening 62 is formed in the side of the housing adjacent to the discs to permit the entry of a suitable tool such as a screw driver or the like, not shown, for engaging the pins for rotating the discs.

A resilient energy storage device providing an elongated tension spring 65 is extended longitudinally of the frame. The spring has a mounting end 66 which is connected by a flexible tie member 67 wound about the hub 55 of the discs 54. The end of the tie member around the hub is secured thereto by a cap screw 68 extended through the end of the tie member in screw threaded relation within a tapped bore in the hub. The tension spring includes an opposite end 69 which has an elongated flexible tie member 70.

A primary sheave 75 is mounted for rotation on a shaft 76 extended outwardly from the end plate 43 of the frame 40 in substantially parallel relation to the shaft 52 mounting the take-up unit 50. The sheave provides a grooved peripheral portion 7 8 and an annular toothed flange axially adjacent thereto. A variable .lever arm member 82 is mounted on the front face of the sheave and provides a surface 84 which spirals outwardly from the shaft 76 to a point adjacent the periphery of the sheave. The tie member 70 on the tensionable end 69 of the spring 65 is wound about the spiral surface 84 and is rigidly connected at its end adjacent to the outer periphery of the sheave by a cap screw 85. As best shown in FIG. 2, a spring biased locking pawl 86 is mounted on the end plate 42 for releasable engagement with the toothed flange 79 of the sheave. The pawl is disengaged by a pivoted lever 87 which is controllable by an elongated cable 88. The cable is fastened at its opposite end to an externally disposed control handle 89, as shown in FIG. 1.

A pair of sets of elongated cables 90 and 91 are connected to and wound about the grooved periphery 78 of the primary sheave 75 and include opposite free ends 92 and 93 respectively individually extended through the chambers 36 on opposite sides of the enclosure. A pair of sets of fastener members 95 and 96 having hooked ends 97 and 98, respectively, are connected at their opposite ends to the free ends of the cables. As best shown in FIGS. 2 and 3, the hooked ends of the fasteners are disposed over the upper edge 19 of the side panels 29 of the lower wall potrion 14. A pair of sets of guide sheaves 99 and 100 mounted on U-shaped brackets 102 and 103, respectively, are individually secured in hooked relation about the lower edge 30 of the opposite side panels 17 of the upper wall portion 25 of the enclosure. Set screws 105 and 105 are screw threadably extended through the U-shaped portion of the brackets to tighten against the side wall panels 29 releasably to hold and to position the peripheries of the guide sheaves in aligned relation with their respective fasteners 95 and 96.

As best shown in FIG. 2, the set of cables 90 extends downwardly over a front double guide sheave 107 on a mounting bracket 108 located at the lower right edge of the forward panel 27. The bracket 108 is releasably secured in such position by a set screw 109. As best shown in FIG. 4, the cables then extend rearwardly and individually over the guide sheaves 99 disposed in longitudinally spaced relation at the lower edge on the side panels 29.

The set of cables 91 at the opposite or left side of the enclosure, as viewed in FIG. 2, extends horizontally transversely through the housing 46 and over a double guide sheave 110 rotatably mounted on the end plate 42 of the frame 40 below the take-up unit 50. The cables depend therefrom as on the opposite side of the enclosure to engage a front double guide sheave 111 at the lower edge of the forward panel 27 and rearwardly through the chamber 36 to the guide sheaves 100 aligned with the fasteners 96. The guide sheave 111 is secured to a U-shaped bracket 112 mounted in such position by a set screw 114, in a manner similar to the bracket 108.

Operation The operation of the described embodiment of the subject invention is believed to be clearly apparent and is briefly summarized at this point. The counterbalaneing system 10 of the present invention is shown in FIG. 2 in a state of equilibrium wherein the force of the tension spring 65 is substantially equal to the weight or force of gravity acting on the upper wall portion 25 of the enclosure 11. However, the upper wall is positively held by the locking pawl 86 engaging the toothed flange 79 of the primary sheave 75. When it is desired to raise the upper wall portion 25 from the full line collapsed position of FIG. 1 to the elevated dashed line position, the pawl 86 is released by actuation of the handle 89 and a slight upward force is exerted anywhere along the lower edge 30 of the upper wall portion. Such upward force partially relieves the force of gravity of the upper wall portion so that the tension spring 65 is permitted to retract and rotate the primary sheave 75 in a counterclockwise direction, as viewed in FIG. 2. Such rotation winds the cables and 91 thereabout to take up slack between the sheave and the free endsof the cables connected to the fasteners and 96 engaging the upper edge 19 0f the lower wall portion 14 of the enclosure. As such elevational movement of the upper wall portion 25 of the enclosure continues, the force of the tension spring 65 gradually decreases. In order to compensate for such decreasing spring force, the tie member 70 is correspondingly moved outwardly from the shaft 76 of the sheave by concurrent rotation of the spiral surface 84 to increase the effective lever arm between the axis of the shaft and the spiral surface. In this way, the spring force and force of gravity acting on the upper wall portion of the enclosure are always substantially equal throughout the full range of travel so that the upper wall portion can be maintained in any selected elevational position between its fully collapsed and fully extended positions. The upper wall portion is then locked in the desired position by releasing the handle 89 which permits re-engagement of the pawl 86 with the toothed flange 79 of the primary sheave.

In order precisely to pre-set the force of the tension spring 65, the take-up unit 50 is utilized. If the upper wall portion 25 tends to drift downwardly from a predetermined position, a screw driver or other tool is inserted through the opening 62 in the housing 46 to engage the pins 56 to ratchet the discs 54 past the locking pawl 58 in a counterclockwise direction to increase the tension of the spring 65. Such rotation of the discs is continued until the spring is tensioned sufiiciently to be in equilibrium with the force of gravity acting on the upper wall portion. On the other hand, if the spring is over-tensioned that ratchet pawl 58 is withdrawn while permitting controlled rotation of the discs in a clockwise direction by the tool extended between the pins after which the pawl is reinserted to hold the discs and the spring in the desired position. Also, the tension of the spring 65 may be further increased within predetermined limits in order to compensate for an additional load such as the boat 34 which may be placed on the top of the enclosure.

It is readily apparent that the structure of the present invention has provided an improved counterbalaneing system which is operable to constrain elevational elements in selected positions of adjustment without mechanical stops. Furthermore, the counterbalaneing system may be employed in a variety of attachment locations and may be readily adapted for mounting on existing telescopic camper enclosures with substantially no alteration. It is also significant that the energy storage portion of the system can be readily adjusted so as to accommodate the weight of additional objects which might be carried on the enclosure without adversely affecting the finger tip control of the enclosure.

Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

l. A counterbalancing system, for an enclosure having telescopically related upper and lower elements, said system being adapted to exert a substantially constant force to maintain the upper element in a selected position of adjustment, comprising a mounting frame; resilient energy storage means anchored to the frame; primary sheave means rotatably mounted on the frame and having a variable lever portion providing a mounting for said energy storage means spaced from its mounting on the frame; a tension member having an end anchored to the sheave to permit winding thereabout at a substantially constant lever arm and providing a free end; means anchoring said free end to said lower element of the enclosure; and guide means mounted on said upper element for engaging said tension member intermediate its ends.

2. A counterbalancing system, for an enclosure having telescopically related upper and lower elements, said system being adapted to exert a constant force to maintain the upper element in a selected position of adjustment, comprising a mounting frame; resilient energy storage means anchored to the frame; a primary sheave rotatably mounted on the frame having a variable lever portion providing a mounting for said energy storage means spaced from its mounting on the frame and including a peripheral portion providing an constant lever arm; a plurality of cables having ends anchored to the sheave to permit winding about said peripheral portion and providing individual free ends; means individually anchoring said free ends to said lower element of the enclosure; and a plurality of guide members providing cable engaging surfaces for guiding said cables between their respective anchors and said primary sheave.

3. In a closure having two telescopically mounted elements in relative upper and lower positions, the combination of a counterbalancing system adapted to exert a substantially constant force to maintain the upper element in a selected position of adjustment and comprising a mounting frame; resilient energy storage means; means anchoring said storage means to the frame; a primary sheave rotatably mounted on the frame; means connecting said energy storage means to the sheave including means to vary the effective lower arm of said sheave; a plurality of cables anchored to the sheave to permit winding thereabout at a constant lever arm, said cables providing individual free ends; means individually anchoring said free ends to said lower element; guide sheaves affording peripheral surfaces for guiding said cables between their respective anchors and said primary sheave; and means anchoring said guide sheaves to said upper element.

4. In an enclosure having two telescopically mounted elements in relative upper and lower positions, the combination of a counterbalancing system adapted to exert a constant force to maintain the upper element in a selected position of adjustment and comprising a mounting frame; resilient energy storage means; adjustable mounting means anchoring said storage means'to the frame; a primary sheave rotatably mounted on the frame in spaced relation to said adjustable mounting means and providing a peripheral portion defining a constant lever arm; a variable lever arm member borne by said sheave connecting the sheave to said energy storage means; a plurality of cables having ends anchored to the sheave to permit winding about said peripheral portion thereof and providing individual free ends; a plurality of fasteners individually connecting said free ends of the cables to said lower element; a plurality of guide members affording surfaces for guiding said cables between their respective anchors and said primary sheave; and means anchoring said guide members to said upper element.

5. A counterbalancing system, for an enclosure having telescopically related upper and lower elements with said system being adapted to exert a constant force to maintain the upper element in a selected position of adjustment and the upper element providing a lower edge movable toward and away from an upper edge on the lower element, comprising a frame; resilient energy storage means; adjustable mounting means anchoring said storage means to the frame; a primary sheave rotatably mounted on the frame in spaced relation to said adjustable mounting means and providing a peripheral portion defining a constant lever arm; a variable lever arm member borne by said sheave connecting the sheave to said energy storage means; a plurality of cables anchored to the sheave to permit winding about said peripheral portion thereof and providing individual free ends; a plurality of fasteners having hook portions individually releasably anchoring said free ends of the cables to said upper edge of the lower element; a plurality of guide sheaves affording peripheral surfaces for guiding said cables between their respective anchors and said primary sheave; and a plurality of mounting members releasably engageable with said lower edge of the upper element mounting said guide sheaves in aligned relation with said fasteners.

6. A counterbalancing system, for an enclosure having telescopically related upper and lower elements with said system adapted to exert a constant force to maintain the upper element in a selected position of adjustment and the upper element providing a lower edge movable toward and away from an upper edge on the lower element, comprising an elongated frame having oposite ends; resilient energy storage means longitudinally extended between said ends of the frame; adjustable take-up means anchoring one end of said storage means to one end of the frame; a primary sheave rotatably mounted on the opposite end of the frame providing a peripheral portion defining a substantially constant lever arm; a variable lever arm member borne by said sheave connecting the sheave to the opposite end of said energy storage means; a plurality of cables anchored to the sheave to permit winding about said peripheral portion thereof and providing in dividual free ends; a plurality of fasteners having hook portions individually releasably anchoring said free ends of the cables to said upper edge of the lower element; a plurality of guide sheaves affording peripheral surfaces for guiding said cables between their respective anchors and said primary sheave; and a plurality of mounting members releasably engageable with said lower edge of the upper upper element mounting said guide sheaves in aligned relation with said fasteners.

7. A counterbalancing system, for an enclosure having telescopically related upper and lower elements, said system being adapted to exert a substantially constant force to maintain the upper element in a selected position of adjustment and the upper element providing a lower edge movable toward and away from an upper edge on the lower element, comprising an elongated frame having op. posite ends; a resilient energy storage spring extended longitudinally of the frame having opposite anchorage and tensionable ends; a spring force adjusting member rotatably mounted on one end of the frame connected to the anchorage end of the spring; a primary sheave rotatably mounted on the opposite end of the frame from said primary sheave mounted on the opposite end of the frame from said adjusting member for rotation about a central axis and providing a peripheral portion defining a constant lever arm; a variable lever arm member borne by said sheave providing connection for said tensionable end of the spring; a plurality of cables anchored to the sheave to permit winding about said peripheral portion thereof and providing individual free ends; a plurality of fasteners having hook portions individually releasable anchoring said free ends of the cables to said upper edge of the lower element; a plurality of guide sheaves affording peripheral surfaces for guiding said cables between their respective anchors and said primary sheave; and a plurality of mounting members releasably engageable with said lower edge of the upper element mounting said guide sheaves in aligned relation with said fasteners.

8. A counterbalancing system, for an enclosure having telescopically related upper and lower elements, said system being adapted to exert a substantially constant force to maintain the upper element in a selected position of adjustment and the upper element providing a lower edge movable toward and away from an upper edge on the lower element, comprising an elongated frame having opposite ends; a resilient energy storage spring extended longitudinally of the frame having opposite anchorage and tensionable ends; a spring force adjusting member rotatably mounted on one end of the frame connected to the anchorage end of the spring; a primary sheave rotatably mounted on the opposite end of the frame from said primary sheave mounted on the opposite end of the frame from said adjusting member for rotation about a central axis and providing a peripheral portion defining a. constant lever arm; a variable lever arm member providing a surface spiraling outwardly from adjacent to the axis of the sheave to a point adjacent to the peripheral portion of the sheave providing connection for said tensionable end of the spring 50 as to equalize the force thereof during tensioning; a plurality of cables anchored to the sheave to permit winding about said peripheral portion thereof and providing individual free ends; a plurality of fasteners having hook portions individually releasably anchoring said free ends of the cables to said upper edge of the lower element; a plurality of guide sheave affording peripheral surfaces for guiding said cables between their respective anchors and said primary sheave; and a plurality of mounting members releasably engageable with said lower edge of the upper element mounting said guide sheaves in aligned relation with said fasteners.

References Cited by the Examiner UNITED STATES PATENTS 900,956 10/1908 Remontet 1678 2,499,478 3/1950 Feser 52-303 3,021,170 2/1962 Cornelius 29623.3

FRANK L. ABBOTT, Primary Examiner.

RICHARD W. COOKE, JR., Examiner.

J. E. MURTAGH, Assistant Examiner. 

3. IN A CLOSURE HAVING TWO TELESCOPICALLY MOUNTED ELEMENTS IN RELATIVE UPPER AND LOWER POSITIONS, THE COMBINATION OF A COUNTERBALANCING SYSTEM ADAPTED TO EXERT A SUBSTANTIALLY CONSTANT FORCE TO MAINTAIN THE UPPER ELEMENT IN A SELECTED POSITION OF ADJUSTMENT AND COMPRISING A MOUNTIN FRAME; RESILIENT ENERGY STORAGE MEANS; MEANS ACHORING SAID STORAGE MEANS TO THE FRAME; A PRIMARY SHEAVE ROTATALY MOUNTED ON THE FRAME; MEANS CONNECTING SAID ENERGY STORAGE MEANS TO THE SHEAVE INCLUDING MEANS TO VARY THE EFFECTIVE LOWER ARM OF SAID SHEAVE; A PLURALITY OF CABLES ANCHORED TO THE SHEAVE TO PERMIT WINDING THEREABOUT AT A CONSTANT LEVER ARM, SAID CABLES PROVIDING INDIVIDUAL FREE ENDS; MEANS INDIVIDUALLY ANCHORING SAID FREE ENDS TO SAID LOWER ELEMENT; GUIDE SHEAVES AFFORDING PERIPHERAL SURFACES FOR GUIDING SAID CABLES BETWEEN THEIR RESPECTIVE ANCHORS AND SAID PRIMARY SHEAVE; AND MEANS ANCHORING SAID GUIDE SHEAVES TO SAID UPPER ELEMENT. 